ApexPC:
One credit is equivelent to $0.01.
Thus - 50 credits = $0.50.
No. While $0.01 is nominally 1 credit, the other direction is not true, see the T&Cs: "Credits have no monetary value."
If you take the "inofficial" conversion rate via gift cards, the value would be about 0,15 US-Cent per credit. The 50 credits in question would then be an equivalent of 7,6 US-Cent. But, they tell the Amateurs that they earned 0.50 $.
How that? Wouldn't that be cheating?
Let me propose to stop talking about the gift cards in this discussion.
It leaves the question, how can 50 credits become 0.50 $?